The present invention relates generally to a piezoelectric ignition lighter, more specifically to an ignition mechanism for a piezoelectric ignition lighter with enhanced safety by increasing actuation load (a load to resist actuation).
Piezoelectric ignition lighters are very convenient because they can ignite by simple actuation or pushing-down of their actuation members. Unfortunately, they are not preferable in terms of safety because they can carelessly ignite by children or other persons who lack in knowledge about their proper use.
One solution to avoid careless or inadvertent ignition of such lighters by persons who have no knowledge of proper use is to increase actuation load as disclosed, for example, in U.S. Pat. No. 5,971,751. That is, a coil spring and a resilient member are disposed inside the actuation button to provide resilient loads of the coil spring and the resilient member to the normal actuation load of the piezoelectric mechanism. In this manner, the ignition actuation mechanism increases actuation load before the piezoelectric mechanism reaching compressed discharge. Also commercially available are lighters having larger than normal spring load inside piezoelectric mechanisms to disable ignition by any person having no knowledge of their proper use.
However, such conventional ignition actuation mechanisms of piezoelectric ignition lighters for improving safety by increasing actuation load are inconvenient to all users. Because the actuation load is heavy over the entire actuation stroke of ignition operation of the piezoelectric mechanism and provides very heavy load from the initial stage of the ignition operation.
It is, therefore, an object of the present invention to provide an ignition actuation mechanism for piezoelectric ignition lighter that avoids unreasonably heavy load at the initial stage of ignition operation but increases the actuation load immediately before discharge. In this arrangement, the present invention effectively avoids misuse of the lighter by any person who lack knowledge about proper use of the lighter while maintaining excellent operation to all normal users.
The ignition actuation mechanism for piezoelectric ignition lighter according to the present invention is a type having a piezoelectric mechanism for generating discharge voltage that causes spark between discharge electrodes to ignite fuel gas by actuation of the actuation member in a single direction. It features in the load (actuation load) resisting operation of the actuation member being sharply increased in the way of actuation stroke for generating discharge voltage by depressing the piezoelectric mechanism. In this manner, the load is light at the initial stage of the ignition operation but becomes heavy at the final stage, thereby avoiding misuse by any person having poor knowledge of proper use but maintaining excellent operability for normal users.
The piezoelectric ignition lighter may have a vertically movable actuation cap assembled, for example, at the top of the piezoelectric mechanism. It is also possible to apply the present invention to a slidable actuation cap that actuates the piezoelectric mechanism by way of a lever or the like.
Preferably, the actuation load is sharply increased at 40%xcx9c10% of the entire actuation stroke before generating the discharge voltage. Operability is poor if the timing to increase the actuation load is too early. On the other hand, children may be able to actuate the igniter if the timing is too late.
Preferably, the maximum actuation load is 30Nxcx9c50N. It is preferable that the actuation load is as high as possible in order to increase safety. However, too heavy actuation load leads to poor operability.
Concrete constructions to increase actuation load of the piezoelectric mechanism in the way of the actuation stroke include, for example, disposing a resilient member between the actuation member and the lighter body to be resiliently compressed in the way of the actuation stroke. A spring load of the piezoelectric mechanism acts as resistance to the actuation member at the initial stage of actuation stroke of the piezoelectric unit and the resilient load of the resilient member is added to the spring load of the piezoelectric mechanism in the way of the actuation stroke.
The resilient member may be a torsion plate that is an integral part of the actuation member.
The necessary torsion plate is made from durable material to resist repeated usage. Such durable torsion plate may be made from polyacetal resin integrally molded with the actuation member. It is also possible to separate the resilient member from the actuation member. The resilient member may be made from a metal spring.